This invention relates to trolley assemblies. In various manufacturing and warehouse facilities, it is common practice to use overhead tracks for moving suspended loads between spaced points within the facility. The loads are typically carried by trolley assemblies which include rollers at their upper ends rollably guiding on the track and further include hangers carried by the rollers and depending downwardly from the rollers to provide a carrier for the suspended loads. Whereas trolley assemblies of this general type provide an effective means of moving loads from point to point within warehousing or manufacturing facilities, the trolley assemblies tend to be rather high maintenance items and tend to have a relatively short product life. Further, when used in facilities where the surrounding environment is hostile or sensitive, such for example as paint spray booths, the trolley assemblies can have the inadvertent effect of contaminating the atmosphere within the spray booth to the detriment of the painting operation being performed within the spray booth and/or contaminates within the spray booth can enter the trolley assemblies to the detriment of the efficient operation of the trolley assemblies.